The present invention relates to driers for particles and aggregates of moist solids, and is particularly adapted to the processing of wet solid materials in the food industry, such as the drying of milk sugar lactose as part of a whey production system. Various types of driers have been used for such purposes in the past. Typical installations have included either drum driers or fluid bed driers. Problems have been encountered in connection with prior processes of such types. In some cases, there has been a problem of proper temperature control to avoid damage to particular materials by sujecting them to too high a temperature or too long an exposure, such that the particles may be appropriately dried, but may be damaged by such handling. Difficulties have also been encountered in the handling and drying of moist solid aggregates of different sizes, where there is a risk of damaging finer particles which are more rapidly dried, as compared to larger or damper aggregates which may require longer drying times or higher drying temperatures in combination with some treatment assist in breaking up the larger aggregates.
Thus I have found a need for an improved drier unit and drier system which can be more easily operated and adjusted with less risk of damge to the sensitive materials to be processed and which has a relatively simple construction which is more economical to build than such prior installations.